ed0e1e4d44
1979 changes to exploits/shellcodes Couchdb 1.5.0 - 'uuids' Denial of Service Apache CouchDB 1.5.0 - 'uuids' Denial of Service Beyond Remote 2.2.5.3 - Denial of Service (PoC) udisks2 2.8.0 - Denial of Service (PoC) Termite 3.4 - Denial of Service (PoC) SoftX FTP Client 3.3 - Denial of Service (PoC) Silverstripe 2.3.5 - Cross-Site Request Forgery / Open redirection SilverStripe CMS 2.3.5 - Cross-Site Request Forgery / Open Redirection Silverstripe CMS 3.0.2 - Multiple Vulnerabilities SilverStripe CMS 3.0.2 - Multiple Vulnerabilities Silverstripe CMS 2.4 - File Renaming Security Bypass SilverStripe CMS 2.4 - File Renaming Security Bypass Silverstripe CMS 2.4.5 - Multiple Cross-Site Scripting Vulnerabilities SilverStripe CMS 2.4.5 - Multiple Cross-Site Scripting Vulnerabilities Silverstripe CMS 2.4.7 - 'install.php' PHP Code Injection SilverStripe CMS 2.4.7 - 'install.php' PHP Code Injection Silverstripe Pixlr Image Editor - 'upload.php' Arbitrary File Upload SilverStripe CMS Pixlr Image Editor - 'upload.php' Arbitrary File Upload Silverstripe CMS 2.4.x - 'BackURL' Open Redirection SilverStripe CMS 2.4.x - 'BackURL' Open Redirection Silverstripe CMS - 'MemberLoginForm.php' Information Disclosure SilverStripe CMS - 'MemberLoginForm.php' Information Disclosure Silverstripe CMS - Multiple HTML Injection Vulnerabilities SilverStripe CMS - Multiple HTML Injection Vulnerabilities Apache CouchDB 1.7.0 and 2.x before 2.1.1 - Remote Privilege Escalation Apache CouchDB 1.7.0 / 2.x < 2.1.1 - Remote Privilege Escalation Monstra CMS before 3.0.4 - Cross-Site Scripting Monstra CMS < 3.0.4 - Cross-Site Scripting (2) Monstra CMS < 3.0.4 - Cross-Site Scripting Monstra CMS < 3.0.4 - Cross-Site Scripting (1) Navigate CMS 2.8 - Cross-Site Scripting Collectric CMU 1.0 - 'lang' SQL injection Joomla! Component CW Article Attachments 1.0.6 - 'id' SQL Injection LG SuperSign EZ CMS 2.5 - Remote Code Execution MyBB Visual Editor 1.8.18 - Cross-Site Scripting Joomla! Component AMGallery 1.2.3 - 'filter_category_id' SQL Injection Joomla! Component Micro Deal Factory 2.4.0 - 'id' SQL Injection RICOH Aficio MP 301 Printer - Cross-Site Scripting Joomla! Component Auction Factory 4.5.5 - 'filter_order' SQL Injection RICOH MP C6003 Printer - Cross-Site Scripting Linux/ARM - Egghunter (PWN!) + execve(_/bin/sh__ NULL_ NULL) Shellcode (28 Bytes) Linux/ARM - sigaction() Based Egghunter (PWN!) + execve(_/bin/sh__ NULL_ NULL) Shellcode (52 Bytes)
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2.5 KiB
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52 lines
No EOL
2.5 KiB
Text
Windows Defender inspects a variety of different archive formats, among others RAR.
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Inspection of mpengine.dll revealed that the code responsible for processing RAR archives appears to be a forked and modified version of the original unrar code; given that it still processes the VMSF_UPCASE filter (which was removed in unrar 5.0), it seems that the code is derived from a version of unrar older or equal than 4.2.4.
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Interestingly, the issue discovered in CVE-2012-6706 (Sophos VMSF_DELTA, and in 2017 unrar) and other signedness issues in the RarVM::ExecuteStandardFilter function were fixed long ago (apparently without a report to upstream, most likely by simply turning the relevant variables from "signed" to "unsigned").
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It appears that this blanket conversion from signed to unsigned ended up introducing a new vulnerability, though:
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From unrar 4.2.4 rarvm.cpp:
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case VMSF_RGB:
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{
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int DataSize=R[4],Width=R[0]-3,PosR=R[1];
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byte *SrcData=Mem,*DestData=SrcData+DataSize;
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const int Channels=3;
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SET_VALUE(false,&Mem[VM_GLOBALMEMADDR+0x20],DataSize);
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if ((uint)DataSize>=VM_GLOBALMEMADDR/2 || PosR<0)
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break;
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for (int CurChannel=0;CurChannel<Channels;CurChannel++)
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The code clearly ensures that PosR is positive from here on.
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This check is no longer present in the binary version of the same code in mpengine, most likely since most signed comparisons in this function have been turned unsigned.
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This causes a vulnerability later in the same function (RarVM::ExecuteStandardFilter)
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Decompile of the mpengine code snippet:
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if ( PosR + 2 < DataSize ) {
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v50 = (_BYTE *)(v39 + PosR);
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do {
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v51 = v50[1];
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*v50 += v51;
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v50 += 3;
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*(v50 - 1) += v51;
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} while ( (unsigned int)&v50[2 - v39] < DataSize );
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Original unrar code:
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for (int I=PosR,Border=DataSize-2;I<Border;I+=3)
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{
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byte G=DestData[I+1];
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DestData[I]+=G;
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DestData[I+2]+=G;
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}
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An attacker that can set PosR to be -2, and DataSize to 1, will bypass the (PosR + 2 < DataSize) check. v50 above will then point to one byte *before* the allocated buffer (v50 respective DestData points into a buffer at index DataSize -- so adding -2 to index 1 will index to -1. The byte from the start of this array will be added into the byte preceding the array.
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A minimal sample RAR file that exhibits these traits & causes mpengine to corrupt memory and crash is attached.
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Proof of Concept:
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https://github.com/offensive-security/exploitdb-bin-sploits/raw/master/bin-sploits/44402.zip |